1. Field of the Invention
The invention relates to an image-based coordinate input apparatus and method and, more particularly, to a coordinate input apparatus and method utilizing buffered images and based on images.
2. Description of the Prior Art
Due to the advantages of enabling users to intuitively input coordinate relative to the display devices via touch method, touch screens have become popular input apparatuses equipped by modern display devices. Touch screens have been widely applied to various electronic products having display devices, such as monitors, laptop computers, tablet computers, automated teller machines (ATM), point of sale, tourist guiding systems, industrial control systems, and so on.
Besides conventional resistive-type and conductive-type touch screens which operators have to input in direct contact, coordinate input method utilizing image capturing devices which operators need not to directly contact the screen has also been adopted. Please refer to the U.S. Pat. No. 4,507,557 to see the prior art regarding image-based coordinate input method utilizing image capturing devices, which is not described herein.
Along with the trends of touch screens performing multi-touch function, image-based coordinate input method is also developed to perform multi-touch function. Please refer to U.S. Pat. No. 7,411,575 to see the related prior art. However, image-based coordinate input method needs sufficient computing resource to judge multi-touch input coordinates in real time.
In addition, image-based coordinate input method very possibly could not judge and distinguish the coordinate positions of multi-touch input points at a detecting interval because these multi-touch input coordinates are quite close.
Accordingly, a scope of the invention is to provide an image-based coordinate input apparatus and method. And more particularly, the image-based coordinate input apparatus and method utilize buffered images to judge multi-touch input coordinate locations. Therefore, when the computing resource is insufficient or the system is not capable of judging and distinguishing the multi-touch input coordinate positions in real time, the image-based coordinate input apparatus and method according to the invention can recall the buffered images to judge the multi-touch coordinate positions.